Turning A Single Bolt Into A Combination Lock

In our search for big-box convenience, we tend to forget that locksmiths once not only copied keys but also created complex locks and other intricate mechanisms from scratch. [my mechanics] hasn’t forgotten, and building a lock is his way of celebrating of the locksmith’s skill. Building a combination lock from a single stainless bolt is probably also showing off just a little, and we’re completely fine with that.

Granted, the bolt is a rather large one – an M20x70 – and a few other materials such as brass rod and spring wire were needed to complete the lock. But being able to look at a single bolt and slice it up into most of the stock needed for the lock is simply amazing. The head became the two endplates, while the shank was split in half lengthwise and crosswise after the threads were turned off; those pieces were later turned down into the tubes and pins needed to create the lock mechanism. The combination wheels probably could have come from another – or longer – bolt, but we like the look of the brass against the polished stainless, as well as the etched numbers and subtle knurling. The whole thing is a locksmithing tour de force, and the video below captures all of it without any fluff or nonsense.

If working in steel and brass isn’t your thing, fear not – a 3D-printed combination lock is probably within your reach. Or laser cut wood. Or even plain paper, if you’re not into the whole security thing.

27 thoughts on “Turning A Single Bolt Into A Combination Lock

  1. They’re not giving enough credit to this guy, the amount of detail he puts into his builds is astounding.

    Even made a second channel were he shows how to make the tools to make these builds…

    1. I make a new one.

      Seriously though, I love this channel. I’ll admit what he does probably goes too far to be considered “restoration” in the strict sense of the word, but who cares. He takes humps of worthless rust that would otherwise be trash and turns them into display pieces.

      I’d much rather watch him create replacement parts than what passes for restoration work on some of the similar channels. Where the solution to most problems seems to be another coat of rattle can spray paint.

      1. It hasn’t got a single bolt in it, since the remaining pieces are no longer the bolt it was originally.

        The lock consists of materials from a single bolt, and some brass rod, and spring wire, and ball bearings… and you might also count the welding rod.

        The headline is like saying “Turning a cup of flour into pancakes”. Yeah, sort-of, if you add sugar, milk, salt and eggs. It would be click-worthy if only flour was used for ingredients. Otherwise it’s just a pancake recipe.

    1. if he’s going to use brass stock, then why use the bolt? get some steel bar of the appropriate diameters instead of splitting and turning the bolt round again.
      I think this is a two bolt project. But it might be hard to find really large brass bolts and it might not look quite as cool with steel thumb wheels.

  2. Subtitle: “I really love my lathe.”

    I’m not sure if it’s cheating or genius to basically turn a bolt into a piece of stainless stock and just take off from there, but you can’t argue with the finished product.

    Double points for using the head as two sheets.

  3. I’m not sure why the brass pieces are brass. I understand that ferric chloride wouldn’t work on stainless steel, but I’m pretty sure that electrochemical milling would.

      1. I certainly do, and you probably do, too. An “electrochemical mill” consists of a plastic tub and a battery. It’s literally exactly what he did with the ferric chloride, but adding a source of current and (possibly) using a different electrolyte.

  4. Despite the previous discussions whether this is a good lock or not, I still find this a very inspiring and fairly well made clip. Maybe with v2.0 the user can set the numeric code ;-)

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